Problem with Open Prices

Found a strange bug in Open Prices:

When you enter 0,29 € and check your entry after uploading it, the system will save 0,28 € in the database instead.

At first I thought I’d made a typo, but even when I entered it again, the system still entered the price incorrectly.

This error also highlights a fundamental problem with the Open Prices system: It assumes that users are perfect and never make typing errors, as there is no provision for users to correct data (at least within a 5-minute window) or to report incorrect entries directly via a click or a ‘flag’.

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Happened to me couple of times as well

Should be 16.9 in both cases. I can’t understand when exactly it happens and the system substracts -1 from last digit

You can edit easily the prices added by you on the website of OpenPrices:

But as far as I know it is not supported in the OFF app still…

Same with reports

Just not in the app still…

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Single mistakes will happen always as it is crowdsorcing project and it is not possible to verify all prices before their adding to the DB and to ask waste too much time from users for every price without damage to project mission, because they won’t be ready to waste their time, if adding proccess will be hard. IMHO, for Open Prices collecting of huge amount of data (more prices from more users) is more important than trying to find and fix every little single mistake. So this basic reporting mechanism is good enough for them and it just should be implemented in the app.
By default we trust a contributor and believe most of added prices by this user will be correct.

In the same time, I believe it should be important to improve moderator tools for finding more systematic mistakes like vandalism, incorrect understanding of adding process by new contributors and similar, because these kinds hurt data quality much more than single mistakes made of human factor.

In future, after getting more price data, it should be possible to build tools for analyzing new added prices, marking them as suspicious and send them to moderators automatically in cases like:

  • We have some product X with 200 prices from 10$ to 20$. And if suddenly DB gets a price where this X product costs 100$, it can be marked “suspicious” by the system and sended automatically to moderators, and only moderator can clear/remove “suspicious” tag.
  • When we get a first price for some product without any price until now and know its category, we can try to compare this first price with prices of other products in the same category.
    • Product X is deodorant. It doesn’t have any price.
    • We get a price for this product for the first time. Let it be 150$
    • We check prices for other products of deodorants “category”, find it is basically have prices between 5-40$ (just random values for illustrating).
    • We recognize it is suspicious this price is 150$, mark it “suspicious” and send to additional moderation check.
  • etc

While these ideas are interesting, I don’t think their implementation should be started right now, because OpenPrices DB is still small and perhaps has not enough data for building and using these tools effectively, which is crucial because team resources are limited and it is not a great idea to waste them for building ineffective tools. So I guess we should wait until price DB will grow and will collect more representative and massive data.

Thanks for the tip!

I had already searched high and low on the OpenFoodFacts website to find where I could enter the prices.

It never occurred to me that I’d have to visit a different website to do that.

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Honestly, in this specific case I’m even happy it is a separate website, because I’m a big hater of main current OFF website because of its totally annoying UX, slowness and uncomfortable navigation while OpenPrices website has much more friendly and usable interface and x5-x10 faster

But basically I agree. It is very fun, that on the web it is two different projects with two different websites, while in the app they are merged into one interface XD